1. Field of the Invention
The present invention relates to a laser device.
2. Description of the Related Art
Until now, various laser devices, or devices each which amplifies light on induced emission and generates in a resonator, have been developed. Laser devices are classified into gas lasers, solid state lasers, and semiconductor lasers by the light gain medium in use. Furthermore, laser devices are classified into lasers with the Fabry-Perot resonators and lasers with the ring resonators by the resonator type in use.
The Fabry-Perot resonator is a resonant cavity of type in which light is resonated by two end mirrors separately faced. The ring resonator is a resonant cavity formed of a ring light propagation path.
In the general laser devices, the oscillation frequency (oscillation wavelength) is determined by the configuration of the resonator and the characteristics of the gain medium. In order to vary the oscillation wavelength, a wave selection element such as a diffraction grating or a thin-film filter arranged on a single resonator forming reflection mirror as well as a drive system for rotating the selection element are prepared to vary the angle of incident light.
However, in such a configuration which including the drive system that rotates the diffraction grating forming a resonator to control the oscillation wavelength, the diffraction grating rotating drive system requires a high accuracy. Consequently, there are disadvantages in that the device manufacturing cost is high and the mechanical drive system has a slow response characteristic.